Industrial rotatable cylinder ironing machines, as exemplified and discussed in U.S. Pat. No. 3,151,408 to Mazzolla, the instant applicant, have long been utilized in large scale industrial, commercial, and institutional laundry operations for the purpose of ironing bed linens, table cloths, towels, various articles of clothing such as uniforms or other garments, and the like. From the very outset of the use of said machines certain operational problems have been encountered, and over the years various inventors have made and patented improvements for overcoming said problems and thereby make industrial rotatable cylinder ironers more functionally operational and efficient. However, among the aforementioned problems which have existed, and to a certain extent continue to exist, the following situations are set forth:
First is the difficulty in not having a satisfactory resilient or cushioning backup member placed circumferentially around the longitudinal dimension of the ironing cylinder, between the fabric roll cover and said ironing cylinder, so that thickness irregularities in various work pieces which are being ironed, such as seams or buttons on garments, may be accommodated by deflective compensation of the resilient backup member as the work piece passes through the plurality of ironing machine cylinders in compression between said roll cover and the steam chest surface, and not encounter work piece jams or damage within the machine, or in the case of buttons, not result in breakage.
An early invention attempting to overcome the aforementioned difficulty in U.S. Pat. No. 1,478,229, to Horne, dated Dec. 18, 1923, wherein a plurality of spring members were arranged and affixed in a staggered pattern upon the ironing cylinder between said cylinder and a fabric covered metal shell roll cover in order to provide the desired resiliency. However, today, with the development of more durable and versatile materials, the metal shell roll cover backed by a multiplicity of springs has been primarily replaced by compressible padding such as earlier described and also shown and discussed in Mazzolla supra.
Second, with the advent of the use of resilient cushioning pads as backup members between the fabric roll cover and ironing cylinder, another difficulty developed. Since the steam chest temperature in an industrial rotatable cylinder ironer is of the order of 300.degree.F or higher, a considerable amount of steam is released from the water-damp work pieces during the ironing process. Released steam permeates the fabric roll cover, condenses within and saturates the backup pad member, which results in the two additional problems of excess heat loss by means of conductive transmission of steam chest heat through the rotatable cylinder, which causes reduced efficiency of the ironing machine, and a combination of oxide and chemical corrosion of the rotatable cylinder as a result of extended periods of exposure of said cylinder surface to cleaning material residues entrained within the condensed steam which saturates the roll cover backup pad.
Various methods have been devised in attempts to overcome the excess heat loss and ironing machine rotatable cylinder corrosion problems resulting from steam condensation thereon, as well as also minimizing cleaning residue of corrosion effects upon said cylinder from contaminated water saturation of the backup pad, such as comprises the subject matters of U.S. Pat. No. 2,762,111 to Morgan, dated Sept. 11, 1956, and U.S. Pat. No. 2,608,749 to Obitz dated Sept. 2, 1952.
The present invention relates to an impermeable pneumatic backup pad device which is designed to more satisfactorily overcome, in a unique and novel manner, the industrial rotatable cylinder ironing machine problems heretofore discussed.
Although pneumatic devices per se, such as the disclosures in U.S. Pat. No. 3,706,119 to Collet, dated Dec. 19, 1972, and U.S. Pat. No. 3,553,970 to Wiswell, dated Jan. 12, 1971, are known, it will become apparent, as hereinafter set forth and claimed, that the present invention is distinguishable from the disclosures heretofore cited in that the present invention has utility features and use characteristics which provide new and useful advantages and improvements neither taught nor anticipated by such prior art.